Mr. Ludgrove shrugged his shoulders. “I know no more than what the paper contains,” he said. “It looks to me like a practical joke. I shouldn’t wonder if some idiot derives amusement from sending these counters broadcast. I daresay he gets the names of people to send them to from the telephone directory.”

“Practical joke? H’m,” said Whyland. “Mind, I’m not denying that a lot of fools do send out these counters to their friends. The Yard has had dozens of cases reported to them. I always said that would happen as soon as people heard about them. But in this case I have seen the envelope in which the counter was sent. It was typed on the same machine as the others, and it was posted in this district, exactly as the others were. Your practical joker has followed his original model pretty closely, don’t you think?”